This invention relates to a slot machine and more particularly to a mechanical slot machine designed to discharge a predetermined number of coins according to the combinations of pictorial symbols arranged on drums which are rotated and stopped in sequence.
Drum type slot machines so designed as to discharge coins according to permutations or combinations of pictures, symbols and the like arranged on a plurality of drums are roughly classified into electrically- and mechanically-driven ones according to drum driving methods. Electrically-driven slot machines generally require a large complicated mechanism and are expensive because coins are discharged after the combinations of pictures displayed on the drums rotated by a motor and stopped using electromagnetic brakes are electrically detected. On the contrary, mechanically-driven slot machines are not only small and simple in construction but also inexpensive because mechanical energy such as the force of springs is utilized to rotate and stop each drum, detect the combinations of pictures displayed thereon and discharge coins without using motors and electromagnets. However, those mechanical slot machines have been either complicated in mechanism and not easy to operate or, on the contrary, too simple in construction to perform such function as makes the game exciting. For instance, some of the former have had special stop buttons, one of each drum, to stop drums rotated by means of an actuating lever; however, the disadvantage is that they require several manual operations from actuating the drums up to stopping them, thus making games complicated. On the other hand, some of the latter have been designed to stop the drums automatically by a stopper incorporated therein, not by stop buttons. The slot machines of this kind have had a disadvantage in that the arrangement of pictures, symbols, etc., on the drums, when stopped, is liable to show a certain pattern or tendency and therefore the fairness of the game is not ensured, because a plurality of drums are simultaneously stopped in a relatively short time but cannot be stopped one by one at intervals.
The present inventor has proposed in U.S. Pat. No. 4,261,571 to provide a mechanical slot machine capable, by a single operation of pulling an actuating lever, of automatically performing a series of actions including rotating drums, stopping them in regular sequence after the lapse of a certain period of time, detecting their stop positions and discharging coins according to the stop positions; however, the problems is that such a slot machine is still lacking in versatility because coins are discharged only when pictures, symbols and the like on each drum, when stopped, are displayed according to a predetermined permutation, that is, only one hitting mode is satisfied. For that reason, the present inventor has further provided a slot machine in U.S. Pat. No. 4,504,058 including supplying rotary drums with a plurality of coin magazines, incorporating projections with each other to arrange a plurality of hit modes, the projections being used to detect the stop position of each drum, and allowing the coin magazines to open individually or simultaneously depending on the hit mode.
According to U.S. Pat. No. 4,261,571, projections are inserted in the notches of index notched disks on the drum sides while the supporting frame is turned by the operation of an actuating lever and a kicker is directly returned to its original position when a hook at the end of the lever pull is released to start the rotation of the drums. However, the problem is that, if the drum is started while the projection is mounted on the index notched disk, the drum will be forced up because of an excessive load and this subjects the drum shaft to an unbalanced load, or if it is not pushed up, the kicker will deform, thus making the starting impossible. In U.S. Pat. No. 4,504,058, because it is so arranged that the shutter on the bottom of a coin magazine is forced to open and shut by transferring the motion of the projections to latches, such a slot machine requires not only a complicated mechanism but also delicate adjustment which tends to easily bring about mechanical failure.